Fuel supply device of an internal combustion engine with a fuel filter

ABSTRACT

A fuel delivery device including a closure element, which closes an opening of a fuel tank and has a cup-shaped receptacle, which opens toward the outside of the fuel tank, contains the fuel filter, and can be closed by a cover element, which can be detachably fastened to the closure element. An elastic sealing ring, which is clamped between the closure element and the cover element, seals the receptacle. In the vicinity of the sealing ring, the closure element has at least one opening via which the receptacle communicates with the interior of the fuel tank. When the cover element is fastened onto the closure element, the sealing ring, starting from a non-deformed original shape, is elastically deformed in such a way that it closes the at least one opening. When the cover element is detached from the closure element, the sealing ring returns to its original shape in which it unblocks the at least one opening. This produces a pressure relief into the interior of the fuel tank when the cover element is detached.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a 35 USC 371 application of PCT/DE01/04501 filed on Nov. 30,2001.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention is based on a fuel supply device of an internal combustionengine with a fuel filter, and particularly to such device including aclosure element closing an opening in a fuel tank and having acup-shaped receptacle containing the fuel filter.

2. Description of the Prior Art

EP 0 612 919 A1 has disclosed a fuel supply device having a closureelement, which closes an opening of a fuel tank and which has acup-shaped receptacle into which the fuel filter is inserted. Thereceptacle can be closed from the outside of the fuel tank by means of acover element, which can be detachably fastened to the closure element.An elastic sealing ring is clamped between the cover element and theclosure element and seals the receptacle. Fuel, which is supplied to theinternal combustion engine under pressure by a delivery unit, flowsthrough the fuel filter. The pressure in the delivery system is usuallymaintained even when the delivery unit is not running; this pressurealso prevails in the fuel filter receptacle. When the fuel filter isreplaced, for which the cover element is detached from the closureelement, pressurized fuel can escape, which is a danger to the personwho is replacing the filter and also represents a fire hazard.

SUMMARY OF THE INVENTION

The fuel supply device according to the invention has the advantage overthe prior art that when the cover element is detached from the closureelement, the sealing ring unblocks the at least one opening connectingthe receptacle to the interior of the fuel tank, which produces apressure relief into the fuel tank so that no pressurized fuel escapesfrom the receptacle. There is therefore no danger to the person who isreplacing the filter and no fire hazard.

BRIEF DESCRIPTION OF THE DRAWINGS

An exemplary embodiment of the invention is shown in the drawings andwill be explained in detail in the subsequent description. In thedrawings:

FIG. 1 schematically depicts a fuel supply device of an internalcombustion engine,

FIG. 2 shows a detail of the device in a view according to the arrow IIin FIG. 1,

FIG. 3 shows an enlargement of a detail labeled III in FIG. 1, with acover element fastened in place, and

FIG. 4 shows the detail when the cover element is detached.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1 to 4 show a fuel supply device of an internal combustion engine10 of a motor vehicle. The engine 10 has an injection system thatinjects fuel into the cylinders of the engine. The motor vehicle has afuel tank 12 that contains a collecting receptacle 14. The collectingreceptacle 14 contains a delivery unit 16, which is comprised of a pumppart and a drive part in the form of an electric motor. When running,the delivery unit 16 aspirates fuel from the collecting receptacle 14and supplies it under pressure to the internal combustion engine 10. Ajet pump 17 delivers fuel from the fuel tank 12 into the collectingreceptacle 14.

The fuel tank 12 has an opening 18, through which the collectingreceptacle 14 can be inserted into it. The opening 18 is closed in asealed fashion by a flange-like closure element 20, which is fastened tothe fuel tank 12 in a manner that is not shown in detail. A cup-shapedreceptacle 22 for a fuel filter 24 is embodied on the closure element 20and points into the interior of the fuel tank 12. The receptacle 22 isopen toward the outside of the fuel tank 12. The fuel filter 24 isinserted into the receptacle 22 from the outside of the fuel tank 12.The fuel filter 24 has an elastically deformable flange 26 at its upperand lower end. When the fuel filter 24 is inserted into the receptacle22, its bottom flange 26 rest with initial stress in the radialdirection against the circumference wall and the bottom 23 of thereceptacle 22 and produces a seal there.

The side of the closure element 20 pointing into the interior of thefuel tank 12 is provided with a fitting 28, which communicates with thereceptacle 22. The fitting 28 has a hydraulic line 30 slid onto it,which is connected to the outlet of the delivery unit 16. The fuelsupplied by the delivery unit 16 travels through the line 30 and thefitting 28 to the dirty side of the fuel filter 24, which is formedbetween its outer circumference and the circumferential wall of thereceptacle 22. The fuel flows through the fuel filter 24 in a radiallyinward direction, to its clean side. The flanges 26 of the fuel filter24 produce a seal between the clean side and the dirty side. A pressurerelief valve 32 can be disposed at the bottom 23 of the receptacle 22and when a predetermined pressure on the clean side of the fuel filter24 is exceeded, this pressure relief valve 32 opens and allows fuel tobe discharged into the fuel tank 12. Preferably, the closure element 20can be comprised of plastic and be produced by means of injectionmolding so that the receptacle 22 and the fitting 28 can be easilyproduced to be of one piece with it.

The receptacle 22 can be closed by a cover element 36, which can bedetachably fastened to the closure element 20. For example, the coverelement 36 can be fastened to the closure element 20 by means of abayonet connection 38. The bayonet connection 38 can be embodied as abayonet catch in which a number of bayonet hooks 40 are embodieddistributed over the circumference of the cover element 36, only one ofwhich is shown in FIGS. 1 and 2. The closure element 20 is provided witha flange 21, which has a number of radial recesses 42 embodied on itsinner rim, corresponding to the number and arrangement of the bayonethooks 40, and in the circumference direction adjacent to these recesses42, ramps 44 are embodied on the inside of the flange 21 oriented towardthe closure element 20. When the cover element 36 is fastened in place,it is placed onto the closure element 20 in the direction of thelongitudinal axis 25 of the receptacle 22, in a rotational position inwhich its bayonet hooks 40 pass through the recesses 42, and then thecover element 36 is rotated into a locking position in which its bayonethooks 40 slide onto the ramps 44, which causes the cover element 36 tobe pulled toward the closure element 20 in direction of the longitudinalaxis 25.

Alternatively, the cover element 36 can also be fastened to the closureelement 20 by means of a screw connection. In this instance, the closureelement 20 can have a with an external thread and the cover element 36can have a shoulder with an internal thread, which is screwed onto theexternal thread of the closure element 20. When the cover element 36 isscrewed in, it is pulled toward the closure element 20 in direction ofthe longitudinal axis 25 of the receptacle 22. It is also possible for aseparate securing ring with an internal thread to be used, whichencompasses the cover element 36 and is screwed onto the external threadof the closure element 20.

A fitting 37 is provided on the cover element 36, protruding outwardfrom it; the cover element 36 is preferably comprised of plastic and isproduced by means of injection molding and the fitting 37 is formed ontoand of one piece with it. The cover element 36 rests against the upperflange 26 of the fuel filter 24 with an initial stress and consequentlyproduces a seal between the clean side and the dirty side of the fuelfilter 24. The clean side of the fuel filter 24 communicates with thefitting 37 to which a line leading to the internal combustion engine 10is connected, through which the fuel supplied by the delivery unit 16travels to the engine 10.

In order to seal the receptacle 22 in relation to the outside, anelastic sealing ring 46 is clamped between the cover element 36 and theclosure element 20. The cover element 36 rests against the closureelement 20 by means of the sealing ring 46 and radially inward from thesealing ring 46, an axial gap 47 remains between the cover element 36and the closure element 20. For example, the cross section of thesealing ring 46 can have an original shape that is approximatelycircular and can be comprised of fuel-resistant rubber or elastomer. Onits side oriented toward the closure element 20, the cover element 36has a circumferential annular groove 48 in which the sealing ring 46 isdisposed. On its side oriented toward the cover element 36, the closureelement 20 has a circumferential annular rib 50, disposed opposite fromthe outer flank of the annular groove 48 of the cover element 36. Inlieu of the annular rib 50, the closure element 20 can also have anannular groove, which is disposed opposite the annular groove 48 of thecover element 36. The closure element 20 has at least one opening 52through which the receptacle 22 communicates with the interior of thefuel tank 12. The at least one opening 52 is disposed radially insidethe sealing ring 46 and directly adjacent to it.

The sealing ring 46 is disposed between the closure element 20 and thecover element 36 and is clamped and therefore elastically deformedduring the fastening of the cover element 36, due to the movement of thecover element 36 directed toward the closure element 20. FIG. 3 showsthe cover element 36 in the position in which it is fastened to theclosure element 20 and the sealing element 46 is in its elasticallydeformed state in which it is pressed flat and is consequently larger inthe radial direction than in its original shape. In this elasticallydeformed state, the sealing ring 46 covers over the at least one opening52 of the closure element 20 so that the receptacle 22 does notcommunicate with the interior of the fuel tank 12. The pressurized fuelsupplied by the delivery unit 16 consequently flows through the fuelfilter 24 and travels out through the fitting 37.

The pressure in the delivery system between the delivery unit 16 and theinternal combustion engine 10 is maintained even when the engine 10 andthe delivery unit 16 are not running. This permits a rapid starting ofthe engine 10. Consequently, there is always an overpressure in thereceptacle 22 in comparison to the ambient pressure. Particles in thefuel flowing through the fuel filter 24, which are held back by the fuelfilter 24 so that they do not travel into the engine 10, can cause thefuel filter 24 to become clogged, thus necessitating its replacement.This can be done easily by detaching and removing the cover element 36from the closure element 20 so that the fuel filter 24 can be removedfrom the receptacle 22 and a new fuel filter can be inserted.

When the cover element 36 is detached from the closure element 20, it ismoved away from the closure element 20 so that the sealing ring 46returns to its approximately circular original shape, which is depictedin FIG. 4. In its original shape, the sealing ring 46 does not cover theat least one opening 52 of the closure element 20, thus unblocking it,allowing the receptacle 22 to communicate with the interior of the fueltank 12 by means of the gap 47 and the at least one opening 52. In theprocess of detaching the cover element 36, the receptacle 22 isconsequently pressure relieved into the interior of the fuel tank 12 bymeans of the at least one opening 52 so that in the subsequent removalof the cover element 36, no pressurized fuel can escape from thereceptacle 22.

The foregoing relates to preferred exemplary embodiments of theinvention, it being understood that other variants and embodimentsthereof are possible within the spirit and scope of the invention, thelatter being defined by the appended claims.

We claim:
 1. A fuel supply device of an internal combustion enginecomprising a fuel filter, a closure element (20) that closes an opening(18) of a fuel tank (12), a cup-shaped receptacle (22) opening towardthe outside of the fuel tank (12) and containing the fuel filter (24), acover element (36) closing the receptacle (22), the cover element beingdetachably fastened to the closure element (20), an elastic sealing ring(46) clamped between the closure element (20) and the cover element (36)and sealing the receptacle (22), the closure element (20) having atleast one opening (52) in the vicinity of the sealing ring (46) viawhich the receptacle (22) communicates with the interior of the fueltank (12), the sealing ring (46), starting from a non-deformed originalshape, being elastically deformed in such a way that it closes the atleast one opening (52) when the cover element (36) is fastened onto theclosure element (20) and when the cover element (36) is detached fromthe closure element (20), the sealing ring (46) returns to its originalshape in which it unblocks the at least one opening (52).
 2. The deviceaccording to claim 1, wherein the cover element (36) and/or the closureelement (20) has an annular groove (48) in which the sealing ring (46)is disposed.
 3. The device according to claim 1, wherein the coverelement (36) is fastened to the closure element (20) by means of abayonet connection (38).
 4. The device according to claim 2, wherein thecover element (36) is fastened to the closure element (20) by means of abayonet connection (38).
 5. The device according to claim 1, wherein thereceptacle (22) is filled with pressurized fuel.
 6. The device accordingto claim 2, wherein the receptacle (22) is filled with pressurized fuel.7. The device according to claim 3, wherein the receptacle (22) isfilled with pressurized fuel.
 8. The device according to claim 4,wherein the receptacle (22) is filled with pressurized fuel.